Engine



.rune 13, 193s.. R, E, KRUG 1,913,399?

ENGINE Filed Aug. l2, 1929 4 sheets-snee: 1f

ZN VEN To?? June 13, 1933. R E KRUG 1,913,399

ENGINE Filed Aug. 12, 1929 4 Sheets-Sheet 2 TONEY June 13, 1933. R, ElKR-UG l 1,913,399

ENGINE Fil-ed Aug. 12, 1929 SheetS-Shee(l 5 June 13, 1933. R. E. kRuG\ENGINE Filed Aug. 12 1929 4 Sheets-Sheet 4 /47' ORNEY Patented June13,` `19133 t noem-r E, Katie; F emilia Grrr, LMNOS; ASSiGNQItZBYMESNE@siem/fleurs, t

aanwerven-AWARE J PATEN'TQFHCE '2Q Kiew AIvBCRAFT ENGINEERING conferir,or s'r. Leurs, mssofunna como;

fvnnernn f Application mea angustia iazejffsefiai No. 385,114.

My invention relates to prime movers and includes a numberoi novelfeatures particularly applicable `to internalcombustionrnotors and otheri features` which may `he used y with any type ofireciprocating motor. c

`The main objectxofmy invention isto produceanengine` unit includingA aplurality of y double acting cylinders arranged endto end y and `havinga common driving rodl through l which the cylinders drive a powershaft.

An additionalfobject of my invention is toi utilize ai group ofthredouble acting cylinders eachoperatingon asix stroke cycle whereineach stroke willjinclude a `power im- 1 pulse on one side ci oneof thepistons.

UA urtlierjdbject of myV invention is to include in such an enginesuitable scavenger air supply andeiihaust means. I also desire "toarrange the cylinders of 2 the engine unit `on opposite sides of thepower shaftland to operate-the power Vshaftby a drivingrodhavingreciprocal movement only.

A` further object ofmy invention -is to provide a power shaft inwhichthe" usual cranklike ofsetsare eliminated. t i ,A i Another object jomyinvention is to pro-l `vide `a horizontal V-engine of comparatively`slight heightthat is particularly adapted for useinaeroplanes,` and inmy copending appli- 1` `cation,lerialNo;371,585, filed J une 17, `1929,

"I illustrate anovel aeroplaney structure made possible `bythe:ilsevofthe engine forming the subject-.matter ofthe present application.` H

These and other detailed objects of my invention are attained by thestructure illustrated" in the accompanying drawings, in which v t i AFigure 1 is averticall section illustrating a portion oan engine unit,andis taken suh- Figure 5 is eideteiil-of lubrietie Vel-ve,

i of the same piston, valves and cams during y the successive strokes othe engine. "fThe `Figure isa detail of an oil discharge valve.` Figure7 is "acomposite section `of one cylinder., `explosion chambers and"valve cams showing relative positions of the piston and ofair, fuelandexhaust valves atboth Vends ofthe cylinder. y Figures 8, 9, 10, 11and 12 are corresponding views showing the successive positions arrowsin-Figures 7 to 12""` indicate `the direction of strokejust beginning."t A y y Figuresl, 14: and 15 illustrate the packinf;r rod ring. y c y yiglllelis a detailsectionftaken approximately ontline 16--16 of Figurel, y y The generi arrangement of myengineis shown in Figure 3;inyiliichthey forward portion of an aeroplane fuselage is indicated atAylateral finsB` extending laterally therefrom andmounting ahorizontally disi posed power plant comprising ninecylin-` dersl,2,3,"i, 5, 6,7;8and@` Thesecylinders are arr anged in," grgups ofthreez"A cylinders each,\e`ach group comprisingone cyly l inderl ononelside of the propeller or power shaft 10` and `tvvo cylinderson theother side .0f the pover shaft- Eechlgroupof ,three cylinders isprovided with a commonpiston rod 11, 12and13, respectively. i f

` 1` The powerplant includes alf; pump lliltor supplying compressed airto the cylinders, and another :pump 15 for exhausting air and the`products of combustion fromthe cylinders.

t l Cylinders 4, `and 64 (Figure 3 and Figure l) compre@ one group 0runt'o the engine,

nested to e 9011119919 `Piston md `or driving rod 1 2gwliich extends"entirelygthrough the cylinder "5 and has its ends securedv to 'theirpiston 18 in cylinders 4 and ,6L y f I; i Wherethe rod passesthrough the`end walls ofthe cylinders, I provide astufling box `and a series ofsplit rings 20 eachhaving step jointat its ends` One ofthe ringsisdetailed in Figures 13,12 and 15 and includes an outer portion 2Oa.brass andf an inner ambient-t 20F the cylinder are provided withexplosion' chambers 60 having suitable valve cages for fuel valves 21,22, respectively, exhaust valves 23 and 24, respectively, and compressedair valves 25 and 26, respectively.

The engine works on a six strokecycle and the cycle for each cylinder isas follows: f e

Left hand end of cylinder Rlghlggend 0f First stroke Fuel intake Exhaustburnedgas Second stroke Compression Receive air Third stroke ExplosionExhaust air Fourth stroke Exhaust burned gas Fuel intake Fifth strokeReceive airY Compression Sixth stroke Exhaust air Explosion Assumingthat the piston shown in cylinder 4 in Figure 1 has just completed afuelintake stroke and is at the beginning of a compression stroke, a detailof the cylinder, piston and its valves will be` found in Figure 8 inwhich each of the valves for the left hand end of the cylinder (isclosed.

f Thefuel, exhaust and air valves for both endsof the cylinder areoperated by a single 'cam shaft 27 provided with three main cams 28, 29and 30 (Figure 2). Cam-*28 operates the two intake valves by thrustingthe valve rods 31 against the valve levers 32 which are pivoted at 33.Cam 29 similarly operates the rods 34v which move the airvalve levers35. Cam 30 operates pinsI 36 which engage bell crank levers 37 pivotedon the cylinder and through the bell cranks operate the valve rods 38which extend to the top of the cylinder and engage levers 39 which inturn engage exhaust valve stems v40. Gear 61 on shaft '10 drives a crossshaft 62 with gearing 59 operating all the cam shafts 27.

Since the valve and valve cam arrange-v ment is the same for eachcylinder (although timed differently), I have applied the same valve andcam reference numerals to the different cylinder structures in order tosimplify description.

Scavenging and cooling air is supplied to each of the cylinders from theair pump 14 through the conduits 48 and the exhaustion of this air andof the burned gases is facilitated by the use of an exhaust pump 15connected with each of the exhaust valves by the conduits 49. I i Y' Thepower shaft 10 is straight from end to end and mounts three cams 50, 51and 52. These cams are set at an angle of 120 to each other about shaft10 and each cam is on the axis of a corresponding piston rod and groupof cylinders.Y Referring to cam 51 and associated parts, driving rod 12includes an intermediate yoke 53 extending on both sides ofthe cam andeach side of the yoke has a slot 54 which receives the power shaft.Anti-friction bearing units 55 and 5571l are journ'alled in the ends ofyoke 53 with their outerraces engaging cam 51. Wedges 57 form means fortaking up play between the cam and the bearings. f

Cam 51,rotating as indicated by the arrow X, has a leading edge j-c anda lagging edge Z-m. The leading edge starts. at ,L apoint at the maximumdistance fromjthe power shaft'.which-'forms vthe axis of the cam. Frompoint L, the leading edge of the cam, throughout the first 128 (j) Vofthe cam movement, rapidly approaches the cam axis. Then follows the arc7c ofl 520I which is substantially described about the'axis as a centerand forms a dwell on the cam throughout Vwhich portion of the cam thepistons will remainstationary. This dwell is followed by an abrupt riscZrwliich corresponds to ythe rapid drop of the .first part ofthe*leading edge of the cam and merges into a sectionm wliiclrwill bringthe cam su'rfacefback to the starting pointk. Y

The piston travel provided cam ishighlyeifective, as will be seen byfollowing a cycle of the engine. For example, starting from the positionshown in Figure 1, thepiston 18 will move to theleft rapidlyl at thebegining of its'stroke, gradually slowin up through'the latter part ofthe-1280 arc,

by this type of vwhereby the piston movement willbe rapid whilethedegree'of compression of the gas is relatively` small,4r and' theypiston movement will: be slower as the degree of compression increases.`Ignition wil occur approximately at the beginning of the52o arc, but asthe piston does not have any further movement towards the end of thecylinder, initialburning of the fuel takes: place without -any spark orpreignition knock.

The force of the explosion is first applied (through the piston, pistonrod and bearing 55) to the cam 51 at the point of the cam loc ated'at4the greatest distance from the power shaft.V .The power generated by anexplosion is very short lived and the quicker it can be deliveredV to arotating shaft the greater will be its value. With my construction, thismaximum power' is applied to the power shaft through the maximum`leverage provided by the mechanism. This construction is Va markedadvantage overthat providedfin the ordinary vinternal'combustion enginein which the crank shaft must travel vapproximately 'a sixth ofarevolution before the piston leverage approaches the maximum, during`which `periodwhilethe exhaust'lvalve liso'pen, the

time the explosiveforceislrelatively ineffec-` tive. At the beginingof-ftheiring stroke numana my engine, the pistonvvill travel very fastthereby allowing the gasto expand quickly. The piston Willgradually losespeed until at y 128 rotation ofthe cam,the piston will have lcompletedits fullstroke. `Since the space for i the exploded gas israpidly increased, the gas v is will expand to a greater-degree andwithless heatithanin an ordinary engine Whichthe expansion is` restrained`for `a greater period oftimerfi l p V Thelexhaust valvel will be openedabout the beginning of the 52 dwellwand theftiming of the exhaust valveopeningacorresponds to` i the 'practice'generally 'followedin internalcombustion engines. Inlmy engine, however, the piston has reached theeXtreme limitof its travel as. th'e exhaust valve opens, Whereas-in theordinary engine the piston continues to travelawayiromthe cylinder headafter the exhaust Valve is opened. v l Hence, with a given fuel charge`and a corresponding piston dis@ placement, there lwill be lesspressure; in the cylinder at the time the exhaust `valve is opened and,therefore, less report through the eiihaust valve, which makes orfa`quieter engine. W ,f

Furthermore, the dwell permits the shaft to ahsorhthe `Inolnentumof thepiston which lisV ordinarily lost because'ofthe immediate reversal ofdirection of the=piston movement .faire end of `a Stroke. `Wahthiseawur.

' uis there is `ampletime for any compressioni'n VVhenl the pistonstarts uponV thefenhaust y stroke "it willagain start foutcfast Aandslow up towards theendand standstill 1to1` ap"- `p1oximatelyf 52. `atthe end of `the stroke,

which "will afford. .ample time to -relieve any pressure `thatmayhavebeenbuilt up onthe uexhaustlst'roke Y .1 ,p

The exhaust valvercmains open through :the next t\vo`1`strokes-` andthroughout the cx'liaust-pugn1p `15 will bewfunotioningto accelcrateltheeXhaust over the speed which would result from 'theordi'nary differencein andthe forcegofthe piston. Y if 5 Afterfthe exhaust valve is openedand pressures in the cylinder and the vatmosphere throughout the period,While the lexhaust 'valve is' open and the exhaust pump-is funcftioning`-4 as described, the compressed air i `Intermediate cams pump14v is supplying air to the samefendof the cylinder, the air intakevalve andthe exhaust valve are at opposite sides andare at top andbottom, respectively, of the` expansionchainher 6() and thepassagewaysdlfrom. thezchamber to the cylinder arefin-` clined,as;indicated in Figure'16,Wherehy the compressed fair` travels diagonally in# Wardly of thecylinder, strike side of the cyl.-`

inderiopposite to `the location ofthe valve,

is reflected againstthe piston and the Aoppo-`V site si de :of thecylinder and is again reflected so as to travel diagonallyoutwardlyofthe c yrlinden-` all` asiodicated by the linef fz/in Figure2.Tl1is-provides `for (a thorough scavenging offthe products ofcombustion andlan adequatexcooling of the cylinder. A reference .to` thesuccessive valve positions, as shown in Figures -7 to llf, will showthatan air stream islalways passingthrough one end of each cylinder or theother. l

`Ilhevvall of each cylinder is provided with an automaticluhricatingvvalve 46 including an inner check ball 47 Iwhich isretracted by the piston `18 `Whenever the latter passes; the d valve andpermits :fthe Jdeposit of" a small A amount of lubricant on thepistonsurface.

pumptnotshovvn). l d ,Y

28 and 293is a cam/11 which operates aplungerl to close an open-` ing 43leading from thecylinder. The pisfH l ton tends to Wipe a quantity ofoil to the ends ofthe cylinder, and thefunction of this opening Slis `topermit the drainage" of lubricat-` ing oil from the lovvermost point ofthecyl-` inder. 4 1 moves 1the"plunger,` toclosed position during`compression and expansion strokes.I y Sinceea h engine unit comprisesthree dou` Vlole` actingcylinders eachhaving `a `six. stroke cycle,there `will be afpower `;impulse on `one piston in fone end of one,cylinder at each stroke. This impulse Willmbe delivered Ito thepowerjshaft andin a direct line to the othertwo pistons of the unitwhich are engagedin otherlstrokes of their cycle, thus eliminating thetortionil stresses set up in the ordinary crank shaft in which the'power `thrustof one piston is appliedto another piston through a lineolf-set for a' substantial portion" of the length of the shaft;`

` "Therengine `assembly 'is particularly advantageous" for aeroplanepofwer `plants in that the horizontally disposed cylinders may belenclosed'in aucomparatively shallovv `fin or `fuselage `construction`whereby `a relatively small `area of head resistance is presented. Itwill be understood thatfthe general ar`` rangement r of `the `engine isnotflilnited to internal` combustionfengines but may be ern bodieduinotherengines. y Obviously, in,` a

lmechanism of the type described, Inanyde-V tails` may be varied withoutdeparting from `the rprincipleof operation and I1 contem- `Valves 46arejsuppliedby means of a suitable uns ' plate the exclusive use of suchmodifications of my invention as come within the scope of my claims.

I claim:

1;. In an engine, a power shaft, three firing cylinders in axialalinement with each other with their common axis extending transverselyof said shaft, two of said-cylinders being located on one side of thepower shaft and one of said cylinders being located on the otherside ofthe power shaft, pistons in said cylinders, and means operativelyconnecting said pistonsand said power shaft.

2. In an engine, two groups of firing cylindersand pistons, each groupcomprising a series of three cylinders arranged end to end, and apowershaft operatively connected to said pistons, two cylinders of Yonegroup being on one side of said shaft and one cylinder of the same groupbeing on the other side of said shaft, and the cylinders of theothergrou'p being arranged conversely with respect to said shaft. 'p

3. I-n an engine, a power shaft, and three groups of firing cylindersand pistons operatively connected to said shaft, each of said groupscomprising cylinders and pistons arranged on opposite sides of saidshaft and applying driving forces tothe same from opposite directions,the appli-cat-ion of driving forces fromeach group occurring 12()degrees apart in the revolution of the power shaft. ,Y n

4., In anengine, a plurality of firing cylinders with their axes lyingin the same plane, a power shaft 'lying in the same plane and extendingtransversely of they axes of said cylinders, said cylinders beingarranged in groups of three cylinders each, each group, includingcylinders on opposite sidesfof said shaftfand the number of cylinders onone side of said shaft in one group differing from the number o-fcylinders on the'same side of sai/d shaft in the next group. y 5.1 In anengine, a series of three firing cylinders varrangedin axial alinement,pistons therein, a power shaft ext-ending transversely of the' axis. ofsaidcylinders and pistons and located between two of them, and a singledriving rod for all of said-pistons and power shafts disposed axiallyofsaid cylinders.

6. In an engine,a series of three firing-cylinders arranged endto,end,'pistons therein, a power shaft extending transversely of saidcylinders and between two ofvthennand a common straight piston rodhaving reciprocal movement onlyin said cylinders and operativelyconnected to said power shaft.l

7.- In anV engine, aseries of three firing cylinders arranged in axialalinement, a single piston rod disposed-axially of said cylinders andextending entirely through l` one of said cylinders and into both of theothers of saidV cylinders, pistons fixedon said rod in eachof'saidcylinders, and a power shaft operatively connected to said pistonrod.

8. In a six cycle engine, three firing cylinder's, individualpistonstherefor, a common piston rodl for said pistons, an air pump, twofuel inlet valves in each cylinder, one on each side of the respectivepiston, twocompressed air valves in each cylinder, one on each side ofthe respective piston, two exhaust valves in each cylinder, one on eachside of the respective piston, two firing elements in each piston, oneon each side of the respective piston, andtiming mechanism providing acycle of fuel inlet, compression, firing, exhaust, air inlet and airexhaust strokes in each cylinder said mechanism providing a power strokeon one side of one piston during each cycle.

.9., An engine structure as described in claim 8 in which the timingmechanism provides firing in the three cylinders consecutively uponsuccessive cycles.

. 10. In an engine, a series of three firing cylinders arranged endtoend, pistons therein, each cylinder and piston being double acting,each end of each cylinder and the corresponding piston end having acycle of six strokes, and the cylinders and pistons being arranged sothat no two cylinder ends and corresponding piston ends arein the samecyclic position at the same time.

11. In a three firing cylinder' double acting engine unit, an air pump,a compressed air conduit, a fuel inlet conduit, and an exhaust conduit,and valves near each end of each of said cylinders controllingrespectively the connections toeach of said conduits. i

12. In an engine of the class described, an air pump, an exhaust pump, adouble acting iringcylinder, a piston, firing mechanism, and valves andvalve operating mechanism at eachend of said cylinderfor admitting fueland admitting air from said air pump on different strokes of said pistonand for opening said cylinder to said exhaust pump after the operationof each of said firing devices and throughout the admission of air, saidvalves and mechanism being arranged so that air from said air pump isbeing admitted to one end or the other of said cylinder at all times.

13. In a double acting internal combustion engine, a firing cylinder, apiston therein, an air pump connected to said cylinder on each side ofsaid piston, valves controlling the admission of pumped air to saidcylinder, and mechanism'operating said val-ves to admit air from saidpump to said cylinder on one side or the other of said piston at alltimes.

14. In an engine, a firing cylinder with walls at both ends, a pistonbetween said walls, a piston rod extending through suitable stuiiingboxes in said walls, and valve gear mechanism and kignition meansoperating on both sides of said piston in timed relation tosuccessivelyadmit fuel, compress the same, explode the same, exhaust thesame, admit air, and exhaust air. p 15. An engine as specified in claim14 which also includes means in addition to said piston for forcingairthrough thecylinder during the air admission cycle. 16. Ina six cycleengine, three firing cylinders, individual pistons therefor, a commonpiston rod orsaid pistons, an air pump, two

fuel inlet valves in each cylinder located von i opposite sides of saidpiston, two compressed air valves in each cylinder located on oppo-`site sides of said piston, two exhaust valves y .151 in each cylinderlocated on opposite sides of said piston, two firing elements in eachpis- `ton located on opposite sides "of said piston,

and timing mechanism providing a cycle of fuel inlet, compression,firing, exhaust, air

inlet, and air exhaust strokes in each end of leach cylinder, saidmechanism providing a power stroke on one side of one piston during eachc, cle.` Y

` 17. i n engine as specified inclaim 14 which `also includes means inaddition to said piston for exhausting uel, admitting air, andexhausting air, during respective cycles.

18. An engine as specified in claim 14 which includes, in addition tosaid piston, a pump for supplying air to the'cylinder anda pump y forexhausting fluids from the cylinder.

19. An engine as specified in claim 14 which Valso includes, in additionto said piston, an

air compressor for supplyingair to the cylinder and an exhaust pump `orexhausting exploded fuel gas and air from the cylinder duringrespectivecycles. f

In testimony whereof I hereunto aiiix my signature this 5th day ofAugust, 1929.

ROBERT E. KRUG.

`esl

